Aleph One

Aleph One is the open source continuation of Bungie's Marathon 2 FPS game engine. Aleph One plays Marathon, Marathon 2, Marathon Infinity, and 3rd-party content on a wide array of platforms, with (optional) OpenGL rendering, Internet play, Lua scripting, and more. Up...
Unity

Unity

Unity is a flexible and powerful development platform for creating multiplatform 3D and 2D games and interactive experiences. It's a complete ecosystem for anyone who aims to build a business on creating high-end content and connecting to their most loyal and...